Expandable Plug Seat

ABSTRACT

Disclosed embodiments relate to methods and devices for setting a plug seat within a downhole well, for example in fracing operations. In an embodiment, the expandable plug seat may include an expandable slip ring and one or more wedge rings. To set the expandable plug seat in place within the casing of the wellbore, longitudinal force would typically be applied to the one or more wedge rings, thereby deforming the expandable slip ring and driving it radially outward and into contact with the casing in the wellbore. In some embodiments, the expandable plug seat may be used with a dissolvable ball, which can be pumped to seat onto the plug seat device for sealing of the wellbore. Once the downstream section of the well has been isolated in this manner, hydraulic fracturing operations can commence. Eventually, the ball may dissolve, allowing access to the wellbore without the need to drill the plug.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional of and claims benefit under 35U.S.C. §119 to co-pending U.S. Provisional Patent Application Ser. No.62/067,594, filed on Oct. 23, 2014, and entitled “Expandable Plug Seat”,which is hereby incorporated by reference for all purposes as ifreproduced in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

Conventional hydraulic fracturing operations (for drilled wells, such asoil and gas wells) typically use drillable zonal isolation devices (suchas composite frac plugs) as the preferred method for treating andcompleting multi-zone horizontal wells. In application, such frac plugswould be located and set within the completion liner (e.g. cased well)one at a time. After placement of each frac plug, high pressurefracturing would be carried out in the reservoir upstream of the plug.Once all fracturing operations have been completed for the well, theplugs would then be drilled out to open the completion liner toproduction.

These conventional fracturing operations can be quite time consuming andcostly, however. Additionally, there is the risk that it might not bepossible to drill out the frac plugs located furthest in the toe of thehorizontal well (e.g. furthest into the well and away from the head ofthe well), for example due to pipe lockup. In such instances, theoperator would lose production for the intervals of the well not drilledout (resulting in a less efficient or productive well). The presentlydisclosed embodiments may solve one or more of these problems byproviding an improved plugging technique, which may not require drillout in order to open the completion liner to full production. Thepresently disclosed embodiments may also provide for improved plug seatsetting. Persons of ordinary skill in the art field will appreciatethese and other possible benefits.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, referenceis now made to the following brief description, taken in connection withthe accompanying drawings and detailed description, wherein likereference numerals represent like parts.

FIGS. 1A-1 through 1A-3 and 1B-1 through 1B-3 illustrates two similarembodiments of an expandable plug seat, having a slip ring and two wedgerings, with FIG. 1A-1 illustrating the first embodiment of a plug seatin unset configuration, FIG. 1A-2 illustrating the plug seat of FIG.1A-1 in set configuration, and FIG. 1A-3 illustrating a ball seated onthe upper wedge ring of the set plug seat of FIG. 1A-2 (thereby sealingthe wellbore); FIG. 1B-1 illustrates a second embodiment of a plug seatin an unset configuration, FIG. 1B-2 illustrates the plug seat of FIG.1B-1 in a set configuration, and FIG. 1B-3 illustrates a ball seated onthe upper wedge ring of the set plug seat of FIG. 1B-2 (thereby sealingthe wellbore);

FIGS. 2A-1 through 2A-3 illustrates an exemplary plug seat devicemade-up into a tool string having a wireline-conveyed power chargesetting tool (e.g. a wireline pressure setting assembly), with FIG. 2A-1showing the top end view of the tool string when the plug seat is in itsunset configuration, FIG. 2A-2 showing the longitudinal cross-sectionview A-A of the tool string, and FIG. 2A-3 showing a radialcross-sectional view B-B of the tool string in unset configuration; andFIG. 2B-1 showing the top end view of the tool string when the plug seatdevice is in its set configuration, FIG. 2B-2 showing the longitudinalcross-section view C-C of the tool string in its set configuration, andFIG. 2B-3 showing a radial cross-sectional view D-D of the tool stringin set configuration;

FIGS. 3A-1 and 3A-2 and 3B-1 and 3B2 illustrate an alternativeembodiment of a plug seat, having a slip ring and only one wedgering/cone (along with additional elements), with FIG. 3A-1 showing anexterior side view of the plug seat in unset configuration and FIG. 3A-2showing a partial cutaway cross-section view of the unset plug seat, andFIG. 3B-1 showing an exterior side view of the plug seat in setconfiguration and FIG. 3B-2 showing a partial cutaway cross-section viewof the set plug seat;

FIGS. 4A-D illustrate schematically a method of employing the plug seatdownhole, with FIG. 4A showing pumping the plug seat to desired depth onwireline and using a setting tool to set the plug seat in place, FIG. 4Billustrates perforating the desired zone above the set plug seat,dropping and pumping a ball to seal the wellbore at the plug seat, andconducting fracturing operations in the well above the set plug seat,FIG. 4C shows how this process may be repeated multiple times until alldesired zones of the well have been fractured, and FIG. 4D illustrateshow over time the dissolvable ball may dissolve to open the completionliner (e.g. cased wellbore) to production;

FIGS. 5A-1 through 5A-4 and FIGS. 5B-1 through 5B-4 illustrate yetanother alternative embodiment of a plug seat, having a slip ring andtwo wedge rings similar to FIGS. 1A-1 through 1A-3 and 1B-1-1B-3 (butfor example, optionally without an external seal on the slip ring), withFIG. 5A-1 showing a partial cut-away cross-section view of an exemplarytool string with the plug seat in unset configuration, FIG. 5A-2 showinga cross-section of the tool string of FIG. 5A-1, FIG. 5A-3 showing aside view of the unset plug seat of FIG. 5A-1, and FIG. 5A-4 showing across-section view of the unset plug seat of FIG. 5A-3; and FIG. 5B-1showing a partial cut-away cross-section view of the exemplary toolstring with the plug seat in set configuration, FIG. 5B-2 showing a sideview of the set plug seat of FIG. 5B-1 (after application of sufficientforce on the wedge rings deforms the slip ring outward into setconfiguration), FIG. 5B-3 showing a cross-section view of the set plugseat of FIG. 5B-2, and FIG. 5B-4 showing a cross-section view of the setplug seat of FIG. 5B-3 with a ball seated on the upper wedge ring of theplug seat (thereby blocking fluid flow through the longitudinal bore ofthe plug seat and/or the cased wellbore in which the plug seat isset/affixed); and

FIGS. 6A-1 through 6A-3 and 6B-1 through 6B-2 illustrate still anotheralternative embodiment of a plug seat, having a slip ring and only onewedge ring, with FIG. 6A-1 showing a partial cut-away cross-section viewof an exemplary tool string with a plug seat in the unset configuration,FIG. 6A-2 shows a side view of the unset plug seat of FIG. 6A-1, andFIG. 6A-3 shows a cross-section of the unset plug seat of FIG. 6A-2; andFIG. 6B-1 showing a cross-section of the set plug seat (afterapplication of sufficient force on the wedge ring deforms the slip ringoutward into set configuration), and FIG. 6B-2 shows a cross-section ofthe set plug seat of FIG. 6B-1 with a ball seated on the wedge ring ofthe plug seat (thereby blocking fluid flow through the longitudinal boreof the plug seat and/or the cased wellbore in which the plug seat isset/affixed).

DETAILED DESCRIPTION

It should be understood at the outset that although illustrativeimplementations of one or more embodiments are illustrated below, thedisclosed systems and methods may be implemented using any number oftechniques, whether currently known or not yet in existence. Thedisclosure should in no way be limited to the illustrativeimplementations, drawings, and techniques illustrated below, but may bemodified within the scope of the appended claims along with their fullscope of equivalents.

The following brief definition of terms shall apply throughout theapplication:

The term “up”, “uphole”, “above”, or the like, when used in reference towell or the tool string for example, shall mean towards the surface ortowards the top or away from the end/toe of the well; similarly, theterm “down”, “downhole”, “below”, or the like shall mean away from thesurface or towards the bottom or end/toe of the well;

The term “ring” shall, when used in reference to an element for usewithin a well or tool string for example, typically mean that theelement has a hole, opening, or longitudinal bore therethrough (forexample, of the sort which might allow fluid flow through the element),and typically such bore would be located approximately along the central(longitudinal) axis of the element;

The term “comprising” means including but not limited to, and should beinterpreted in the manner it is typically used in the patent context;

The phrases “in one embodiment,” “according to one embodiment,” and thelike generally mean that the particular feature, structure, orcharacteristic following the phrase may be included in at least oneembodiment of the present invention, and may be included in more thanone embodiment of the present invention (importantly, such phrases donot necessarily refer to the same embodiment);

If the specification describes something as “exemplary” or an “example,”it should be understood that refers to a non-exclusive example;

The terms “about” or approximately” or the like, when used with anumber, may mean that specific number, or alternatively, a range inproximity to the specific number, as understood by persons of skill inthe art field (for example, +/−10%); and

If the specification states a component or feature “may,” “can,”“could,” “should,” “would,” “preferably,” “possibly,” “typically,”“optionally,” “for example,” “often,” or “might” (or other suchlanguage) be included or have a characteristic, that particularcomponent or feature is not required to be included or to have thecharacteristic. Such component or feature may be optionally included insome embodiments, or it may be excluded.

Embodiments may relate generally to methods and devices for setting aplug seat within a downhole well, for example in advance of fracingoperations. The disclosed expandable plug seat embodiments typicallyinclude an expandable slip ring (which in some embodiments mayoptionally have an elastomeric seal on its exterior) and one or morewedge rings (and in some embodiments, the plug seat may consistessentially of or consist only of a slip ring and one or more wedgerings). For example, typical embodiments might include dual wedge rings,with an upper wedge ring located above the slip ring and a lower wedgering located below the slip ring. In other embodiments, a single wedgering might be located with respect to (for example, above) the slipring. To set the expandable plug seat in place within the casing of thewellbore, longitudinal force would typically be applied to each of theone or more wedge rings, thereby deforming the expandable slip ring anddriving it radially outward and into contact with the casing in thewellbore (due to the interaction of the wedge-like shape of the one ormore wedge rings with the inner (radial) surface of the slip ring). Insome embodiments, deformation of the slip ring may be plastic and/orelastic (and most typically there would be plastic deformation of theslip ring). In some embodiments, the expandable plug seat may be usedwith a dissolvable ball (which might be either dissolvable metal ordissolvable polymer), which can be pumped to seat onto the plug seatdevice (for example, directly on the upper wedge ring). Once thedownstream section of the well has been isolated in this manner,hydraulic fracturing operations can commence. Eventually, the ball maydissolve, allowing access to the wellbore without the need to drill theplug. And in some embodiments, one or more element of the plug seat mayalso dissolve, providing additional radial space in the well (forexample, for future production).

So for example, in an embodiment, the plug seat device might comprise anexpandable (for example, solid) slip ring (which optionally may have anexternal elastomeric seal), wherein the expandable slip ring is operableto expand by deforming (plastically and/or elastically) radially outward(upon application of sufficient force on its inner diameter); and one ormore wedge rings (for example, operable to slide longitudinally and)located with respect to the slip ring so that application of sufficientlongitudinal force on the wedge rings operates to drive the slip ringradially outward (e.g. causing the deformation of the slip ring).Typically, each wedge ring would comprise a wedge-like shape (forexample, with the outer diameter of the wedge ring at one end (typicallythe end farther away from the slip ring in the unset configuration)being larger than the outer diameter of the wedge ring at the oppositeend (typically the end closer to the slip ring in the unsetconfiguration)) having an angled vertex/outer surface ranging from about5-10 degrees (or alternatively 3-20 degrees), for example. And, the slipring typically would be operable to deform (plastically and/orelastically) radially outward upon application of force from the wedgerings (for example, when sufficient longitudinal force is applied to theone or more wedge rings, driving the one or more wedge rings furtherinto the slip ring, and thereby driving the slip ring radially outwarddue to the wedge-shape of the wedge rings). Furthermore, the expandableplug seat typically would have an (initial) unset configuration and aset configuration (e.g. after application of sufficient longitudinalforce on the wedge rings has driven the slip ring radially outward intocontact with the inner surface of the casing and/or wellbore, or untilthe slip ring has been driven outward so that is outer diameter isapproximately equal to the inner diameter of the cased wellbore inquestion). In the unset configuration, the slip ring typically has aninitial outer diameter that is less than the inner diameter of thecasing and/or wellbore (for example, allowing the plug seat device to berun downhole); one wedge ring (e.g. the upper wedge ring) is typicallylocated above the slip ring; and optionally one wedge ring (e.g. thelower wedge ring) may be located below the slip ring, for example with(only) the vertex of each wedge ring initially being located within(e.g. radially inward of and contacting the inner diameter/surface of)the slip ring (such that the remainder of the wedge rings typicallywould be located outside the slip ring and would not contact the slipring in the unset configuration). So, the plug seat would betransitioned from its unset configuration to its set configuration byapplication of sufficient longitudinal force on the one or more wedgerings (for example, sliding the wedge rings longitudinally towards eachother and/or inward of the slip ring—for example, with more of the wedgering(s) located within the slip ring). In the set configuration, the oneor more wedge rings would have been driven (and are located) furtherwithin the slip ring (for example, with the upper wedge ring beingdriven downward into the slip ring and the lower wedge ring being drivenupward into the slip ring), thereby driving the slip ring radiallyoutward via deformation (plastic and/or elastic) of the slip ring untilthe outer diameter of the slip ring contacts the inner diameter of thecasing and/or wellbore with sufficient force to hold the slip ring inplace during fracing operations (e.g. the outer diameter of the slipring in the set configuration is approximately equal to and contacts theinner diameter of the casing and/or wellbore). In other words, the slipring may be set (e.g. moved from the unset configuration to the setconfiguration) by application of sufficient longitudinal force on theone or more wedge rings, driving the one or more wedge ringslongitudinally further within the slip ring. Thus, the slip ring isconfigured so that it is operable to transition from its unsetposition/shape/size (with an outer diameter less than the inner diameterof the cased wellbore, for example) to its set position/shape/size (withouter diameter equal to the inner diameter of the cased wellbore, forexample).

The slip ring may optionally have a plurality of anchoring teeth on itsouter surface, configured to more securely attach the slip ring in placeon the inner surface of the cased wellbore (in the set configuration),for example with the teeth operable/configured to penetrate the casingslightly upon setting of the plug seat (for example, penetrating about0.010-0.030 inches). The slip ring may optionally also have a pluralityof longitudinal slots (which typically might not penetrate all the waythrough the slip ring, but merely would be indentations forming athinner wall cross-section at locations in the slip ring—although inother embodiments, the slots could form openings in the slip ring) whichmay be located radially around the circumference of (e.g. the outersurface) of the slip ring. For example, each such longitudinal slotmight have a width of about 0.25 inches, a length of about 2.17 inches,and a depth to not fully penetrate the slip ring, but rather to leave athin web (for example about 0.030 inches thick). An exemplary embodimentmight have about 15 such slots spaced evenly around the exteriorcircumference of the slip ring. And while some embodiments of the slipring may have an elastomeric (or other) seal element located on itsouter/exterior surface, in other embodiments the slip ring may beconfigured to effectively form a seal when driven into contact with thecased wellbore (e.g. an effective seal might be formed without the useof any such separate seal element).

Typically, the plug seat device does not contain any additionalretention elements (such as a body lock ring or mandrel) beyond the slipring and/or wedge rings (so for example, the plug seat may consistessentially of or consist of only the slip ring and one or more wedgerings). Additionally, typically the plug seat device would not contain aseparate ball seat (e.g., the ball could be landed directly on the upperwedge ring). So for example, the plug seat of some embodiments mightconsist essentially of (or consist of) only the slip ring and one ormore wedge rings. In some embodiments, the slip ring may comprise anouter surface, which may comprise a plurality of anchoringteeth/barbs/ridges in some embodiments for securing/attaching/anchoringthe slip ring in place on the inner surface of the casing and/orwellbore (providing a better lock/grip than friction alone).Additionally, the optional elastomeric seal (typically located on theouter/exterior surface of the slip ring in embodiments having such aseal) typically would be configured/operable to effectively seal fluidflow about the exterior of the plug seat device when set in place withinthe casing (although in other embodiments, such an effective seal mightbe formed by contact of the slip ring body itself against the casedwellbore, without any need for a separate seal element). Typically, theoptional seal diameter would be slightly larger than the outer diameterof the slip ring (for example, larger than the slip teeth diameter) toallow for compression when set. Such a seal might be rated for 10,000psi differential pressure at 350 degrees Fahrenheit. Exemplary sealmaterials might be either Nitrile or Aflas.

Often, the plug seat device might be operable or configured to work inconjunction with a sealing ball/plug. Such a ball might be formed of adissolvable material (which might be metallic or polymeric materialoperable to dissolve over time (for example, approximately 1-5 days)under exposure to elevated temperature (for example a range ofapproximately 150-250 degrees Fahrenheit) and either brine (for exampleKCL brine) or acid (for example approximately 2-5 pH range)). Oneexample of such a dissolvable material might be TervAlloy or similarmaterials sold by Terves, Inc. Another example of such dissolvablematerial might be polymer from Bubbletight LLC. In some suchembodiments, the slip ring and/or one or more wedge rings in the setconfiguration might be configured to have an inner diameter sufficientlylarge to allow for access to the wellbore via tubing or wireline (suchthat they do not need to be drilled out to allow for production of thewell). In some other embodiments, the one or more wedge rings and/or theslip ring of the plug seat might also be formed of such dissolvablematerial (e.g. material operable to dissolve over time (for example,approximately 1-5 days) under exposure to elevated temperature (forexample a range of approximately 150-250 degrees Fahrenheit) and eitherbrine (for example KCL brine) or acid (for example approximately 2-5 pHrange)). For example, the one or more wedge rings and/or slip ring mightbe formed of the same dissolvable material as the sealing ball/plug.This would allow the plugged wellbore to open (after the timeframeneeded for fracing, for example) without the need for drilling. And insome embodiments, the plug seat device may be configured/operable to bemade-up into a tool string with a wireline-conveyed power charge settingtool (e.g. a wireline pressure setting assembly) and/or a perforatinggun assembly. Such a tool string may allow the plug seat to be set andthe wellbore to be perforated in one wireline trip downhole (e.g. priorto fracturing the zone).

FIGS. 1A-1 through 1A-3 illustrate a first embodiment of a plug seatdevice 10, while FIGS. 1B-1 through 1B-3 illustrate a second, similarembodiment of a plug seat device (with the primary difference betweenthe embodiments of FIGS. 1A-1 through 1A-3 and 1B-1 through 1B-3 beingthe angle of the wedge rings and/or the depth that the wedge rings slidewithin the slip ring during setting). FIG. 1A-1 illustrates an exemplaryplug seat device 10 in its unset configuration (e.g. its initialconfiguration, allowing it to be run downhole into position within thewellbore). The plug seat device of FIG. 1A-1 has a slip ring 20 and twowedge rings 30 and 40. The slip ring 20 of FIG. 1A-1 is configured as asolid ring operable to deform (e.g. plastically and/or elastically)radially outward upon application of force from the wedge rings (e.g.when sufficient longitudinal force is applied to the wedge rings), andin the unset configuration of FIG. 1A-I, the slip ring 20 has an outerdiameter that is less than the inner diameter of the casing/wellbore 5(to provide sufficient clearance so that the plug seat can be rundownhole). For example, when the wedge rings 30, 40 (each of which maybe operable to slide longitudinally upon application of sufficientlongitudinal force) are driven towards the slip ring 20(longitudinally), the angled surfaces of the wedge rings 30, 40 woulddrive the slip ring 20 radially outward and into contact with thewellbore/casing 5. By way of example, the slip ring 20 of FIGS. 1A-1through 1A-3 and 1B-1 through 1B-3 might be formed of AISI 8620 material(fully annealed), 10-12% elongation, which should provide sufficientplasticity to allow for the slip ring to transition from the unsetconfiguration/position to the set configuration/position. The slip ring20 of FIG. 1A-1 typically has an elastomeric seal 22 (although this maybe optional) about its outer/exterior surface (for example, extendingcircumferentially about the exterior of the slip ring), and theelastomeric seal 22 is configured/capable/operable of providing aneffective seal to prevent fluid flow about the exterior of the slip ring20 in its set configuration. Furthermore, the slip ring of FIG. 1A-itypically would have a plurality of gripping or anchoring elements 25(typically termed teeth) on its exterior surface (for example, teeth,barbs, or ridges operable to bite/dig into the inner diameter surface ofthe casing/wellbore 5 when the plug seat is set, to provide a moreeffective hold to lock the set plug seat in place).

In the embodiment of FIG. 1A-1, the two wedge rings 30 and 40 eachtypically have an angle of about 10 degrees (so for example, the outersurface of the wedge rings might have an angle of about 10 degrees withrespect to a line parallel to the centerline of the plug seat device).Typically, in the unset configuration shown in FIG. 1A-1, one wedge ringwould be located on either side of the slip ring 20 (for example, withan upper wedge ring 30 located above the slip ring 20, and the lowerwedge ring 40 being located below the slip ring 20), and typically onlythe vertex 32, 42 of the wedge rings would be located initially withinthe slip ring 20 and contacting the inner surface of the slip ring (e.g.the remainder of the wedge rings 30, 40 would initially be locatedoutside the slip ring, for example longitudinally). In other words,there is a gap of space longitudinally between the vertexes of the wedgerings 30 and 40 in the unset configuration (and the gap typically wouldbe approximately the length of the slip ring 20). And typically, thewedge rings 30, 40 would have an outer diameter that at their furthestend is less than the inner diameter of the casing/wellbore 5 (to againensure that the plug seat device as a whole has an outer diameter thatis less than the inner diameter of the casing/wellbore 5, so that thereis sufficient clearance to allow for running of the plug seat devicedownhole). For example in the unset configuration the outer diameter (ofthe far end of) the wedge rings 30, 40 would typically be spaced awayfrom the inner diameter of the casing/wellbore 5 about a distance lessthan the thickness of the slip ring 20). By way of example, the wedgerings 30, 40 would typically be formed of a material which issufficiently strong to drive the slip ring outward (under application ofsufficient longitudinal force), such as AISI 4140 material with 110minimum yield strength.

FIG. 1A-2 illustrates the same plug seat device from FIG. 1A-1 in itsset configuration (e.g. after application of sufficient longitudinalforce on the wedge rings, to drive the slip ring radially outward andinto contact with the casing/wellbore, thereby fixing the plug seat 10into position in the well). Longitudinal force typically would beapplied to the top of the upper wedge ring 30 and to the bottom of thelower wedge ring 40, thereby driving the wedge rings closer together andfurther into the slip ring 20. By way of example, the settinglongitudinal force for some embodiments might be approximately10,000-30,000 lbs·F. As the wedge rings 30, 40 are driven inward, theirangled surfaces act to transmit the force to the slip ring 20, therebydriving the slip ring 20 radially outward until it contacts and is setin the casing/wellbore 5. So in FIG. 1A-2 (which shows the plug seat inits set configuration), the wedge rings 30, 40 are closer together, withmore of the wedge rings 30, 40 length located within the slip ring 20.The slip ring 20 of FIG. 1A-2 has a larger outer diameter, which isapproximately equal to the inner diameter of the casing/wellbore 5. Thisallows the anchoring teeth 25 on the exterior surface of the slip ringto anchor securely to the casing/wellbore 5 (in a securely affixingmanner), and the elastomeric seal 22 on the exterior of the slip ring 20to fit snuggly (in a sealing manner) against the inner surface of thecasing/wellbore 5.

FIG. 1A-3 then shows how the open longitudinal bore of the set plug seatdevice 10 may be sealed by seating a ball 50 onto the upper wedge ring30. This would typically be done in advance of fracturing operationsuphole of the plug seat 10. The ball 50 would typically have a diameterlarger than the inner diameter of the wedge ring 30, and would typicallyseat directly onto the upper wedge ring 30. In some embodiments, theball 50 would be formed of dissolvable materials. For example, the ball50 might be formed of dissolvable metallic material operable to dissolveover time (for example, approximately 1-5 days) under exposure toelevated temperature (for example a range of approximately 150-250degrees Fahrenheit) and either brine (for example KCL brine) or acid(for example approximately 2-5 pH range). One example of such a materialmight be TervAlloy or similar materials sold by Terves, Inc.Alternatively, the ball might be made of a dissolvable polymer material,such as made by Bubbletight LLC for example. In some embodiments, theball might have a protective coating, for example to delay dissolutionof the ball (although in other embodiments, the well chemistry might beused (perhaps along with a protective coating) to delay or control thetiming of dissolution). The use of such a dissolvable ball 50 mightallow for the plug seat 10 to be temporarily sealed by a ball, but to beoperable to open at a later time without the need for drilling. In someembodiments, the wedge rings 30, 40 and/or slip ring 20 might also beformed of similar dissolvable materials (which might allow for a largerbore without the need for drilling).

FIGS. 1B-1 through 1B-3 illustrate a similar plug seat 10, having wedgerings 30, 40 with an angle of about 5 degrees (e.g. the outer surface ofthe wedge rings would have an angle of about 5 degrees with respect to aline parallel to the centerline of the plug seat 10). FIG. 1B-I showsthe plug seat in unset configuration, FIG. 1B-2 shows the plug seat inset configuration, and FIG. 1B-3 shows the plug seat when sealed by aball 50. In FIG. 1B-2, the wedge rings 30, 40 may be driven togetheruntil their vertexes contact. It should be understood that sufficientlongitudinal force applied to the wedge rings may effectively set theslip ring in the casing/wellbore, as discussed above.

In some embodiments, the plug seat 10 (for example as shown in FIGS.1A-1 through 1A-3 and 1B-1 through 1B-3, although other plug seatembodiments would also apply) may be made-up into a tool string having awireline-conveyed power charge setting tool (e.g. a wireline pressuresetting assembly, such as Baker Style #20 WL Setting Tool), for applyingthe longitudinal force required to set the plug seat 10 in place in thecasing/wellbore. For example, FIGS. 2A-1 through 2A-3 and 2B-1 through2B-3 illustrates such an exemplary tool string, with FIG. 2A-1 through2A-3 showing the tool string when the plug seat 10 is in the unsetconfiguration, and FIG. 2B-1 through 2B-3 showing the tool string whenthe plug seat 10 is in the set configuration. FIG. 2A-1 shows a top sideview of the tool string in unset configuration, while FIG. 2A-2 shows alongitudinal cross-sectional view A-A (showing the plug seat device 10in unset configuration and in place in line with the setting tool 60),and FIG. 2A-3 shows a radial cross-sectional view B-B. FIG. 2B-1 shows atop side view of the tool string in set configuration, while FIG. 2B-2shows a longitudinal cross-sectional view C-C (showing the plug seatdevice 10 in set configuration and in place in line with the settingtool 60), and FIG. 2B-3 shows a radial cross-sectional view D-D. In someembodiments, the tool string may also include a perforating gun (notshown, but for example, located above the plug seat 10). Such a toolstring configuration might allow setting of the plug seat andperforating of the well using only a single trip downhole (prior tofracturing the zone). Then, for example, a dissolvable ball might beseated on the plug seat to allow for fracing operations (for example,during the time before the ball and/or wedge rings dissolve).

FIGS. 3A-1 through 3A-2 and 3B-1 through 3B-2 illustrate an alternativeembodiment of a plug seat. The plug seat of FIGS. 3 A-1 through 3A-2 and3B-1 through 3B-2 comprises a dissolvable mandrel or body, a dissolvabletapered cone/wedge ring (similar to that discussed above), a dissolvablelock ring, and/or a solid expandable slip ring (similar to the slip ringdiscussed above) having an inner seal and an outer seal (although suchseals may be optional, with one or both being omitted from someembodiments). The dissolvable materials might be the same or similar tothose discussed above, for example. As described above, the wedgering/cone would typically have a wedge-like portion having an angledouter surface (for example, ranging from about 3-20 degrees). Themandrel has a flow-through passage, which may allow flow bypass prior tofracturing operations. The mandrel also features a ball seat on theuphole end. Typically, the mandrel would also comprise an angled outersurface portion located (below the slip ring) and oriented to work inconjunction with the wedge ring (when sufficient longitudinal force isapplied to the wedge ring) to drive the slip ring radially outwardduring setting of the plug seat (e.g. causing plastic deformation of theslip ring as it moves from the unset position to the set position). Forexample, in the embodiment of FIGS. 3 A-1 through 3A-2 and 3B-1 through3B-2 the angled outer surface portion of the mandrel typically mightmatch the angle of the wedge ring and/or be 3-20 degrees. Similar to theembodiments described above, the plug seat of FIGS. 3 A-2 and 3B-1through 3B-2 has an initial, unset configuration, and a setconfiguration. FIGS. 3A-1 through 3A-2 show the plug seat in its unsetconfiguration, while FIGS. 3B-1 through 3B-2 show the plug seat in itsset configuration. To set the plug seat in place in the wellbore, alongitudinal force would be applied to the dissolvable lock ring and/ortapered cone/wedge ring while the mandrel is held in place. The forcewould serve to deform (e.g. plastically and/or elastically) theexpandable solid slip ring, driving it radially outward until itcontacts the inner diameter of the casing/wellbore. Once the plug seatis anchored, a dissolvable ball (which, for example, might be formed ofthe same dissolvable material as the dissolvable elements of the plugseat) may be dropped and pumped to seat on the mandrel (e.g. the ballseat) of the plug seat, to allow for fracturing operations. Over time,the dissolvable elements of the plug seat (and the ball) will dissolve,for example leaving only the slip ring and/or seals behind (which shouldnot inhibit production flow and typically would have a sufficientlylarge inner diameter to allow for access to the wellbore via tubingand/or wireline). In other embodiments, however, even the slip ringmight be formed of dissolvable material (for example, similar to thatdescribed above), such that only the elastomeric seals (if any) might beleft un-dissolved in the wellbore. In some embodiments, the ball and/ordissolvable elements of the plug seat device might have a protectivecoating, for example to delay dissolution (although in otherembodiments, the well chemistry might be used (perhaps along with aprotective coating) to delay or control the timing of dissolution).

FIGS. 5A-1 through 5A-4 illustrate an alternative embodiment of a plugseat (similar to that shown in FIGS. 1A-1 through 1A-3 and 1B-1 through1B-3 for example) in unset configuration, while FIGS. 5B-1 through 5B-4illustrate the same embodiment in set configuration. FIGS. 5A-1 and 5A-2illustrate the plug seat 510 within an exemplary tool string (e.g. theplug seat may be removably coupled to the tool string, for example witha wireline-conveyed power charge setting tool), with FIG. 5A-1 showing apartial cut-away cross-section view of the tool string and FIG. 5A-2showing a full cross-section of the tool string (in unsetconfiguration). FIG. 5A-3 illustrates (in a side view) just the plugseat 510 in unset configuration, while FIG. 5A-4 illustrates the sameunset plug seat 510 via cross-section view. So as clearly shown in FIGS.5A-3 through 5A-4, the plug seat 510 has two wedge rings 530 and 540configured to interact (via longitudinal sliding) with the slip ring 520(typically with one wedge ring 530 located above the slip ring 520, andone wedge ring 540 located below the slip ring 520). In other words, inFIG. 5A-4 (with the plug seat unset), only the vertex of each wedge ring530, 540 is initially located within the slip ring 520, but the wedgerings 530, 540 are configured to slide further into the slip ring 520upon application of sufficient longitudinal force (e.g. shifting fromunset to set configuration).

The slip ring 520 in this unset configuration has an outer diameterwhich is configured to be less than the inner diameter of the casedwellbore (for which the plug seat is intended to be used), and isoperable/configured to deform (plastically and/or elastically) underapplication of force from the wedge rings 530, 540 (in order to shiftoutward from the unset to the set configuration/position). The wedgerings 530, 540 also have a maximum outer diameter which is less than theinner diameter of the cased wellbore (although typically the differencebetween the maximum outer diameter of the wedge rings 530, 540 and theinner diameter of the cased wellbore is less than or equal to thethickness of the slip ring, for example after deformation to the setposition). In FIG. 5A-3, the slip ring 520 comprises a plurality ofteeth 525 on its outer/exterior surface, typically located about thecircumference of the slip ring outer surface. While the teeth 525 may beoriented in various ways (e.g. to form a secure hold onto the casedwellbore), in FIG. 5A-3 the teeth on the upper portion of the slip ring520 face one direction (for example, angled downward), while the teethon the lower portion of the slip ring 520 may face another direction(for example, angled upward). The slip ring 520 of FIG. 5A-3 alsocomprises a plurality of longitudinal slots 527 located evenly about itsouter surface circumference. For example, in FIG. 5A-3, there may be 15such slots (which typically would not penetrate the slip ring in theembodiment of FIG. 5A-3 (although in other embodiments, the slots couldpenetrate the slip ring to form openings), but are merely locations ofthinness of the slip ring 520, such as indentations), with each slot 527typically having a width of about 0.25 inches, a length of about 2.17inches, and a depth to not fully penetrate the slip ring, but ratherleave a thin web (for example about 0.030 inches thick).

As discussed above, the slip ring 520 is typically made of a materialoperable to deform from unset to set configuration upon application ofsufficient force (radially) via the wedge rings 530, 540. And typically,the wedge rings 530, 540 and/or the slip ring 520 may be formed ofdissolvable material (as discussed above). On the other hand, if thewedge rings and/or slip ring are not dissolvable (for example, if only adissolvable ball is used to close the bore), then they (e.g. one orboth) may instead have a bore (e.g. an inner diameter) which issufficiently large in the set position/configuration to allow for accessto the wellbore (below the set plug seat) via tubing or wireline, suchthat they do not need to be drilled out to allow for downholework/production below the set plug seat in the wellbore. And asdiscussed above, the wedge rings 530, 540 typically have a wedge-likeshape (for example, in cross-section), with the outer surface having anangle (for example, with respect to a line parallel to the longitudinalbore centerline) ranging from about 3-20 degrees (or for example,alternately 5-20, 5-10, or 10-20 degrees). And as discussed above, theseat plug of FIGS. 5A-1-5A-4 and 5B-1-5B-4 may consist essentially of orconsist of only the slip ring 520 and wedge rings 530, 540.

Upon application of sufficient longitudinal force on the wedge rings530, 540 (for example, with the setting tool pressing down on the upperwedge ring 530 directly, while the lower wedge ring 540 is pressed upagainst by an insert 508 which interacts with the setting tool in thetool string to transmit upward longitudinal force to the lower wedgering), the wedge rings 530, 540 move (e.g. slide longitudinally) furtherinto the slip ring (for example, towards each other), with theirwedge-like shape driving the slip ring 520 to deform (plastically and/orelastically) outward to the set configuration/position as shown in FIGS.5B-1 through 5B-4 for example (when its outer diameter is configured tobe approximately equal to the inner diameter of the cased wellbore,providing a secure attachment of the plug seat to the cased wellbore, asdiscussed above). FIG. 5B-1 illustrates in partial cross-section theplug seat 510 (in set configuration) in place within a tool string,while FIG. 5B-2 shows just the plug seat 510 in set configuration from aside view, FIG. 5B-3 shows the same set plug seat 510 in cross-section,and FIG. 5B-4 shows the set plug seat 510 with a ball 550 (typicallydissolvable) seated on the upper wedge ring 530 to close/seal the bore(for example, in preparation for fracing). In the set configurationshown in FIGS. 5B-2 through 5B-3, the wedge rings 530, 540 have beendriven closer together and are substantially located within the slipring 520 (e.g. the gap between the set wedge rings is much smaller thanin the unset configuration shown in FIG. 5A-4 for example). The slipring 520 of FIG. 5B-3 (in the set configuration) typically would have anouter diameter approximately equal to the inner diameter of the casedwellbore at issue. Additionally, embodiments may optionally include ashear ring or tab (for example, attached to the slip ring and/or thelower wedge ring) in the unset configuration of FIG. 5A-1, which may beoperable/configured to be sheared once the setting tool provides therequired setting force. This may limit the amount of force applied tothe plug seat, and may also allow for the plug seat to disconnect fromthe setting tool once set. Thus, these figures clearly illustrate anexemplary plug seat embodiment (for example, without an externalelastomeric seal) in both the unset and set configuration, and personsof skill would understand the construction and operation of such a plugseat 510 based on these figures.

FIGS. 6A-1 through 6A-3 illustrate another alternative embodiment of aplug seat (similar to that shown in FIGS. 1A-1 through 1A-4 and 1B-1through 1B-4 and/or FIGS. 3A-1 through 3A-2 and 3B-1 and 3B-2 forexample) in unset configuration, while FIGS. 6B-1 through 6B-2illustrate the same embodiment in set configuration. FIG. 6A-1illustrates the plug seat 610 within an exemplary tool string (e.g. theplug seat may be removably coupled to the tool string, for example witha wireline-conveyed power charge setting tool), with FIG. 6A-1 showing apartial cross-section view of the tool string (in unset configuration).FIG. 6A-2 illustrates (in a side view) just the plug seat 610 in unsetconfiguration, while FIG. 6A-3 illustrates the same unset plug seat 610via cross-section view. So as clearly shown in FIGS. 6A-2 through 6A-3,the plug seat 610 has only one wedge ring 630 (typically located abovethe slip ring 620), which is configured to interact (via longitudinalsliding) with the slip ring 620. In other words, in FIG. 6A-3, only thevertex of the wedge ring 630 is initially located within the slip ring620 (in unset configuration), but the wedge ring 630 is configured toslide further into the slip ring 620 upon application of sufficientlongitudinal force (e.g. shifting from unset to set configuration).

Similar to the discussion above regarding FIGS. 5A-1 through 5A-4 and5B-1 through 5B-4, the slip ring 620 in this unset configuration has anouter diameter which is configured to be less than the inner diameter ofthe cased wellbore (for which the plug seat is intended to be used), andis operable/configured to deform (plastically and/or elastically) underapplication of force from the wedge ring 630 (in order to shift outwardfrom the unset to the set configuration/position). The wedge ring 630also has a maximum outer diameter which is less than the inner diameterof the cased wellbore (although typically the difference between themaximum outer diameter of the wedge ring 630 and the inner diameter ofthe cased wellbore is less than or equal to the thickness of the slipring, for example after deformation to the set position). In FIG. 6A-3,the slip ring comprises a plurality of teeth 625 on its outer/exteriorsurface, typically located about the circumference of the slip ringouter surface. While the teeth 625 may be oriented in various ways (e.g.to form a secure hold onto the cased wellbore), in FIG. 6A-3 the teethall face one direction (for example, angled downward). The slip ring 620of FIG. 6A-3 also comprises a plurality of longitudinal slots 627located evenly about its outer surface circumference. For example, inFIG. 6A-3, there may be up to 15 such slots (which in this embodimentmay penetrate the slip ring 620 forming openings through the slip ring,but which in other similar embodiments might merely be locations ofthinness of the slip ring, such as indentations), with each slottypically having a width of about 0.25 inches and a length of about 2.17inches (and some embodiments having a slot depth penetrating the slipring, while other embodiments might have a depth to not fully penetratethe slip ring, but leaving a thin web (for example about 0.030 inches)).

As discussed above, the slip ring 620 is typically made of a materialoperable to deform from unset to set configuration upon application ofsufficient force (radially) via the wedge ring 630. And typically, thewedge ring 630 and/or the slip ring 620 may be formed of dissolvablematerial (as discussed above). On the other hand, if the wedge ringand/or slip ring are not dissolvable (for example, if only a dissolvableball is used to close the bore), then they (e.g. one or both) mayinstead have a bore (e.g. an inner diameter) which is sufficiently largein the set position/configuration to allow for access to the wellbore(below the set plug seat) via tubing or wireline, such that they do notneed to be drilled out to allow for downhole work/production below theset plug seat in the wellbore. And as discussed above, the wedge ring630 typically has a wedge-like shape (for example, in cross-section),with the outer surface having an angle (for example, with respect to aline parallel to the longitudinal bore centerline) ranging from about3-20 degrees (or for example alternately, 5-20, 5-10, or 10-20 degrees).And as discussed above, the seat plug of FIGS. 6A-1 through 6A-3 and6B-1 through 6B-2 may consist essentially of or consist of only the slipring 620 and wedge ring 630.

Upon application of sufficient longitudinal force on the wedge ring 630,for example with the setting tool pressing down on the upper wedge ring630 directly, the wedge ring 630 moves (e.g. slide longitudinally)further into the slip ring (for example, with most of the length of thewedge ring located within the slip ring), with the wedge-like shapedriving the slip ring 620 to deform (plastically and/or elastically)outward to the set configuration/position as shown in FIGS. 6B-1 through6B-2 for example (when its outer diameter is configured to beapproximately equal to the inner diameter of the cased wellbore,providing a secure attachment of the plug seat to the cased wellbore, asdiscussed above). FIG. 6B-1 illustrates in cross-section just the plugseat 610 (in set configuration), while FIG. 6B-2 shows the set plug seat610 with a ball 650 (typically dissolvable) seated on the wedge ring 630to close/seal the bore (for example, in preparation for fracing). In theset configuration shown in FIGS. 6B-1-6B-2, the wedge ring 630 has beendriven farther into the slip ring and is substantially located withinthe slip ring 620. The slip ring 620 of FIG. 6B-1 (in the setconfiguration) typically would have an outer diameter approximatelyequal to the inner diameter of the cased wellbore at issue.Additionally, embodiments may optionally include a shear ring or tab(for example, attached to the slip ring) in the unset configuration ofFIG. 5A-1, which may be operable/configured to be sheared once thesetting tool provides the required setting force. This may limit theamount of force applied to the plug seat, and may also allow for theplug seat to disconnect from the setting tool once set. Thus, thesefigures clearly illustrate an exemplary plug seat embodiment (forexample, without an external elastomeric seal) in both the unset and setconfiguration, and persons of skill would understand the constructionand operation of such a plug seat 610 based on these figures.

One or more of the plug seat device embodiments described above mayallow for an improved method of fracturing a well, especially forexample when used in conjunction with a dissolvable ball/plug.Typically, such a method of performing downhole operations (such asfracing) within a (typically cased) wellbore uses an expandable plugseat (which, for example, might include a slip ring and one or morewedge rings located with respect to the slip ring so that application ofsufficient longitudinal force on the wedge rings operates to drive theslip ring radially outward) and includes the step of applying alongitudinal force onto the one or more wedge rings (thereby driving thewedge rings towards one another and/or deeper into the slip ring),thereby deforming (e.g. plastically and/or elastically) the slip ringradially outward into contact with the casing/wellbore (in order to seatthe plug seat in the casing/wellbore and/or move the plug seat from theunset position to the set position). In some embodiments, thelongitudinal force may be applied to the wedge rings by awireline-conveyed power charge setting tool (e.g. a wireline pressuresetting assembly). Typically, the plug seat might not contain anyadditional retention elements (such as body lock ring or mandrel) beyondthe slip ring and/or wedge ring(s). Additionally, the plug seattypically would not contain a separate ball seat; rather, the ball wouldbe landed directly on the upper wedge ring. So in some embodiments, theplug seat may consist essentially of (or consist of) only the slip ringand one or more wedge rings.

The method may further comprise the step of positioning the plug seatwithin the wellbore (i.e. locating the plug at the proper locationdownhole within the wellbore for sealing of the wellbore for fracturingof a zone). Oftentimes, the plug seat may be run downhole in conjunctionwith a wireline-conveyed power charge setting tool (e.g. a wirelinepressure setting assembly) and/or a perforating gun assembly (e.g. allthree would be run downhole together at the same time). This may allowfor more efficient setting of the plug seat and perforating of the well(reducing the number of separate trips run downhole). Typically, such amethod would include making-up a tool string comprising the plug seat, awireline-conveyed power charge setting tool (e.g. a wireline pressuresetting assembly), and/or a perforating gun assembly, and thenpositioning the plug seat in the wellbore, setting the plug seat usingthe wireline-conveyed power charge setting tool (e.g. a wirelinepressure setting assembly), and perforating the well casing, all in asingle trip downhole.

Once the plug seat has been set in the wellbore and the well/casing hasbeen perforated, the wellbore can be sealed to allow for fracturing ofthe well upstream of the plug seat. Typically, the wedge rings maycomprise at least an upper wedge ring located above the slip ring, andthe method may further comprise landing (e.g. pumping) a dissolvableball/plug onto the upper wedge ring (to isolate/seal the downstreamsection of the well). In other words, the ball typically would landdirectly on the upper wedge ring, without a separate ball seat. In someembodiments, the ball may be formed of dissolvable material (operable todissolve over time (for example, approximately 1-5 days) under exposureto elevated temperature (for example a range of approximately 150-250degrees Fahrenheit) and either brine (for example KCL brine) or acid(for example approximately 2-5 pH range). One example of such a materialmight be TervAlloy dissolvable metallic material or similar materialssold by Terves, Inc. Another example of such material might bedissolvable polymeric material by Bubbletight LLC. And in someembodiments, the plug seat (or at least portions of the plug seat, suchas the one or more wedge rings and/or the seal ring) would be formed ofdissolvable material (for example, operable to dissolve over time (forexample, approximately 1-5 days) under exposure to elevated temperature(for example a range of approximately 150-250 degrees Fahrenheit) andeither brine (for example KCL brine) or acid (for example approximately2-5 pH range). Again, exemplary materials might be TervAlloy or similarmaterials sold by Terves, Inc., or dissolvable polymeric material byBubbletight LLC. So, the slip ring and/or one or more wedge rings may beformed of the same dissolvable material as the ball (or in someembodiments, the wedge ring(s) and/or slip ring may be dissolvable,while the ball might not be).

Once the set plug seat has been sealed (isolating the downstream portionof the well), the method might include fracturing a zone of the wellabove the set and sealed plug seat (e.g. with the ball in place on theupper wedge ring). In most instances, the wellbore in question wouldcomprise a horizontal portion (e.g. a horizontal well), having a toe anda heel. Typically, the initial plug seat is set towards the toe of thehorizontal portion of the well (e.g. farthest downhole). The process(for example, setting a plug seat, perforating the casing, sealing theplug seat with a dissolvable ball/plug, and fracturing the zone)typically would be repeated one or more times from the toe of thehorizontal portion of the well towards the heel. Then, the ball and/orplug seat would dissolve (over about 1-5 days, due to exposure to wellconditions (e.g. elevated temperature, acid and/or brine), without theneed for drilling to open the wellbore). In other words, the wellboremight be accessed downstream of the location of the set plug seat(s) viatubing and/or wireline without drilling the ball and/or plug seat (dueto the dissolvable nature of the ball and/or plug seat), allowingproduction of the well without drilling the ball and/or plug seat.

FIGS. 4A-D illustrate such an exemplary method. In FIG. 4A, a plug seat410 is pumped to the desired depth on a wireline, and is set in placeusing a setting tool. Typically, this initial plug seat 410 would be setin place towards the toe 401 of the horizontal well 402. And typically,the plug seat 410 would be set in place by application of longitudinalforce upon the wedge ring(s) of the plug seat 410, thereby driving theslip ring of the plug seat 410 radially outward and into contact withthe casing/wellbore 405. Once the plug seat has been set, the well zonewould be perforated above the set plug seat (as shown in FIG. 4B).Oftentimes, a single tool string would be made-up having the plug seat410, a setting tool (not shown), and a perforating gun (not shown). Thiswould allow the plug seat 410 to be set and the well zone to beperforated in a single trip downhole.

Once the well has been perforated (and the tool string, for examplehaving the setting tool and or perforating gun, has been removed), adissolvable ball 450 might be dropped and pumped downhole until it isseated on the plug seat 410 (as shown in FIG. 4B). Once the well hasbeen sealed, fracturing operations may be performed in the desired zoneabove the plug seat 410 (as shown in FIG. 4B). This process may berepeated until all desired zones have been fractured (e.g. placingmultiple plug seats, typically proceeding from the toe 401 towards theheel 402 of the horizontal well). FIG. 4C shows an exemplary well, inwhich a plurality of plug seats have been set in place and sealed (viadissolvable ball), and fracturing operations have occurred in a zoneabove each of the plug seats. In such an exemplary method, there wouldbe no need to drill out the plugs (after all fracturing operations havebeen completed). Rather, the plugs (e.g. the ball/plug and/or wedgering(s)) would disappear after a predetermined period of time(dissolving under well conditions, as shown for example in FIG. 4D). Inthe embodiment of FIG. 4D, the ball and wedge ring(s) would be formed ofdissolvable material, such that after the predetermined period of time,only the slip ring (and any elastomeric seal on the slip ring) of eachplug seat would remain in place in the well (although in otherembodiments, only the ball might be dissolvable). In such instances, theinner diameter of the set slip ring would be sufficiently large that itwould not interfere with production of the well (for example, allowingpassage of tubing and/or wireline devices). In other embodiments,however, the slip ring (as well as the ball and wedge ring(s)) might beformed of dissolvable material (for example, to provide an even largerlongitudinal bore). Once the dissolvable elements have disappeared, theoperator may proceed with well start-up and production activities.

While various embodiments in accordance with the principles disclosedherein have been shown and described above, modifications thereof may bemade by one skilled in the art without departing from the spirit and theteachings of the disclosure. The embodiments described herein arerepresentative only and are not intended to be limiting. Manyvariations, combinations, and modifications are possible and are withinthe scope of the disclosure. Alternative embodiments that result fromcombining, integrating, and/or omitting features of the embodiment(s)are also within the scope of the disclosure. And logic flows for methodsdo not necessarily require the particular order shown, or sequentialorder, to achieve desirable results. Other steps may be provided, orsteps may be eliminated, from the described flows/methods, and othercomponents may be added to, or removed from, the describeddevices/systems. So, other embodiments may be within the scope of thefollowing claims.

Accordingly, the scope of protection is not limited by the descriptionset out above, but is defined by the claims which follow, that scopeincluding all equivalents of the subject matter of the claims. In theclaims, any designation of a claim as depending from a range of claims(for example #-##) would indicate that the claim is a multiple dependentclaim based of any claim in the range (e.g. dependent on claim # orclaim ## or any claim therebetween). Each and every claim isincorporated as further disclosure into the specification and the claimsare embodiment(s) of the present invention(s). Furthermore, anyadvantages and features described above may relate to specificembodiments, but shall not limit the application of such issued claimsto processes and structures accomplishing any or all of the aboveadvantages or having any or all of the above features.

Additionally, the section headings used herein are provided forconsistency with the suggestions under 37 C.F.R. 1.77 or to otherwiseprovide organizational cues. These headings shall not limit orcharacterize the invention(s) set out in any claims that may issue fromthis disclosure. Specifically and by way of example, although theheadings might refer to a “Field,” the claims should not be limited bythe language chosen under this heading to describe the so-called field.Further, a description of a technology in the “Background” is not to beconstrued as an admission that certain technology is prior art to anyinvention(s) in this disclosure. Neither is the “Summary” to beconsidered as a limiting characterization of the invention(s) set forthin issued claims. Furthermore, any reference in this disclosure to“invention” in the singular should not be used to argue that there isonly a single point of novelty in this disclosure. Multiple inventionsmay be set forth according to the limitations of the multiple claimsissuing from this disclosure, and such claims accordingly define theinvention(s), and their equivalents, that are protected thereby. In allinstances, the scope of the claims shall be considered on their ownmerits in light of this disclosure, but should not be constrained by theheadings set forth herein.

Use of broader terms such as comprises, includes, and having should beunderstood to provide support for narrower terms such as consisting of,consisting essentially of, and comprised substantially of. Use of theterm “optionally,” “may,” “might,” “possibly,” and the like with respectto any element of an embodiment means that the element is not required,or alternatively, the element is required, both alternatives beingwithin the scope of the embodiment(s). Also, references to examples aremerely provided for illustrative purposes, and are not intended to beexclusive.

Also, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as directly coupled or communicating witheach other may be indirectly coupled or communicating through someinterface, device, or intermediate component, whether electrically,mechanically, or otherwise. Other examples of changes, substitutions,and alterations are ascertainable by one skilled in the art and could bemade without departing from the spirit and scope disclosed herein.

What is claimed is:
 1. An expandable plug seat device operable to be setwithin casing for a wellbore, comprising: an expandable slip ring,wherein the expandable slip ring is configured to expand by deformingradially outward; and one or more wedge rings configured to slidelongitudinally upon application of sufficient longitudinal force andlocated with respect to the slip ring so that application of sufficientlongitudinal force on the one or more wedge rings operates to drive theslip ring radially outward; wherein: the one or more wedge rings eachcomprise a wedge-like shape; the expandable plug seat has an unsetconfiguration and a set configuration; in the unset configuration, theslip ring has an initial outer diameter that is less than the innerdiameter of the casing; and in the set configuration, the outer diameterof the slip ring is configured to contact the inner diameter of thecasing with sufficient force to hold the slip ring in place duringsubsequent operations.
 2. The device of claim 1, wherein the one or morewedge rings each comprise a vertex having an angle ranging from about3-20 degrees.
 3. The device of claim 1, wherein the expandable slip ringcomprises an external elastomeric seal.
 4. The device of claim 1,wherein the slip ring is configured to expand by plastic deformationradially outward into contact with the casing of the wellbore; andwherein, in the set configuration, the outer diameter of the slip ringcontacts the inner diameter of the casing with sufficient force to forma seal therebetween.
 5. The device of claim 1, wherein the slip ring isconfigured to expand by elastic deformation radially outward intocontact with the casing of the wellbore; and wherein, in the setconfiguration, the outer diameter of the slip ring contacts the innerdiameter of the casing with sufficient force to form a sealtherebetween.
 6. The device of claim 1, wherein the slip ring comprisesan outer surface, and the outer surface comprises a plurality ofanchoring teeth for securely attaching the slip ring in place on theinner surface of the casing.
 7. The device of claim 1, wherein the slipring comprises an outer surface and a plurality of slots extendinglongitudinally and located radially around a circumference of the outersurface of the slip ring.
 8. The device of claim 1, wherein the deviceconsists essentially of only the slip ring and the one or more wedgerings.
 9. The device of claim 1, wherein the one or more wedge rings areformed of dissolvable material.
 10. The device of claim 1, wherein theslip ring is formed of dissolvable material.
 11. The device of claim 9,wherein the slip ring is formed of dissolvable material.
 12. The deviceof claim 1, further comprising a ball configured to seat on the one ormore wedge rings and formed of dissolvable material.
 13. The device ofclaim 1, wherein the device is configured to be made-up into a toolstring with a wireline-conveyed power charge setting tool.
 14. Thedevice of claim 1, further comprising a mandrel and a lock ring, andwherein the mandrel comprises a ball seat and an angled outer surfaceportion located and oriented to work in conjunction with the wedge ringto drive the slip ring radially outward from the unset position to theset position when sufficient longitudinal force is applied to the wedgering.
 15. The device of claim 1, wherein the one or more wedge ringscomprise two wedge rings; and wherein, in the unset configuration, onewedge ring is located below the slip ring and one wedge ring is locatedabove the slip ring.
 16. The device of claim 1, wherein the one or morewedge rings comprise a single wedge ring; and wherein, in the unsetconfiguration, the wedge ring is located above the slip ring.
 17. Amethod of performing downhole operations within a cased wellbore using aplug seat, wherein the plug seat includes a slip ring and one or morewedge rings located with respect to the slip ring so that application ofsufficient longitudinal force on the one or more wedge rings operates todrive the slip ring radially outward, the method comprising the stepsof: applying a sufficient longitudinal force onto the one or more wedgerings, thereby deforming the slip ring radially outward into contactwith the casing.
 18. The method of claim 17, wherein the slip ringdeforms plastically upon application of sufficient force via the one ormore wedge rings, until the slip ring contacts the casing of thewellbore to securely affix the plug seat to the casing.
 19. The methodof claim 17, wherein the slip ring deforms elastically upon applicationof sufficient force via the one or more wedge rings, until the slip ringcontacts the casing of the wellbore to securely affix the plug seat tothe casing.
 20. The method of claim 17, wherein the longitudinal forceis applied to the one or more wedge rings by a wireline-conveyed powercharge setting tool.
 21. The method of claim 17, wherein the one or morewedge rings comprise an upper wedge ring located above the slip ring;the method further comprising landing a dissolvable ball on the upperwedge ring.
 22. The method of claim 21, wherein the ball dissolves dueto exposure to well conditions over time, thereby opening the wellborewithout the need for drilling.
 23. The method of claim 17, furthercomprising making-up a tool string comprising the plug seat, awireline-conveyed power charge setting tool, and a perforating gunassembly.
 24. The method of claim 23, further comprising positioning theplug seat in the wellbore, setting the plug seat using thewireline-conveyed power charge setting tool, and perforating the wellcasing, all in a single trip downhole.
 25. The method of claim 24,wherein the wellbore comprises a horizontal portion, having a toe and aheel; the method further comprising repeatedly setting plug seat,perforating the wellbore, sealing the wellbore by landing ball on theplug seat, and fracturing the wellbore using a plurality of plug seatsand balls proceeding from the toe of the horizontal portion of thewellbore towards the heel.